Kangaroos – The 100 Days Project: Day 61 
The Major Roos:
Photo: Greg Schechter [CC BY 2.0]
One of the things that distinguishes the Antilopine kangaroo/wallaroo (Macropus antilopinus) from the rest of the major roos is that the others perhaps don’t have to worry quite so much about crocodiles (an enticement to visit Kakadu National Park suggests one might be 'lucky' enough to see there a crocodile ‘take’ an Antilopine). And one of the things that would seem also to distinguish the Antilopine, and perhaps worry those who would try to think about it – one can’t imagine it would worry the Antilopines themselves (I’m sure they know exactly who they are) – is a certain amount of taxonomic confusion. Are they Antilopine kangaroos, Antilopine walleroos, or Antilopine wallabies? They seem to have been called all three.
Antilopine. The name seems to have been given them by John Gould (1804-1881 [Day 71]), who provides us with this regal portrait:
It’s not clear whether Gould ever saw a live one. The chances, given that the port of Darwin was not even settled until 1869, are that he didn’t. Certainly he hadn’t when, in 1841, he described ‘four new species of kangaroo’ to the Zoological Society of London, at which point, having only just returned from Australia, he had been working from only a skull and skin. The fur, it seems, had reminded him of the pelt of an antelope.
The Antilopines are the northernmost of the major macropods, inhabiting what we might call the monsoonal belt, perhaps not the hottest of Australian macropod ranges (though it must be very close), but certainly the most humid and highest in rainfall. They exist in two distinct populations, a western, from the Kimberley through to the western and part of the southern coast of the Gulf of Carpentaria, and an eastern, covering much of the Cape York peninsula. These populations (the Kimberley/Gulf, and the Cape York) are separated by approximately five hundred kilometres of relatively dry grassland, largely across the base of the Gulf of Carpentaria.
DNA studies have determined that, while not a great deal distinguishes one population from the other, the populations seem to have separated several thousand years ago (creating the eastern population) and that, quite curiously, none of the females from the Cape York population appear to have ever gone back, while there seem to have been, in accommodating seasons, occasional male visitors from the west to the east. What we need make of this I simply don’t know, but we are left with the vision of some males now and again making a huge trek to visit their cousins. (How do they know about their cousins? Do they hand down legends, generation to generation?)
Terence Dawson (Kangaroos, CSIRO, 2012) provides us with the following succinct description:
Male Antilopine Kangaroos are reddish-tan above and much paler on the front or undersurface. The tips of the paws and hind feet are black. The females are more variable in colour. They usually have a pale grey head and forequarters but the rest of the back may be all grey or reddish tan, like the males. (25)
Intriguingly, and as Dawson goes on to describe, the males have ‘a characteristic swelling of the nose behind the nostrils. This enlargement of the nasal passages is probably related to the need of a large animal to lose heat by panting in this hot, humid climate; kangaroos pant through their nose with their mouth closed.’ Curious that this feature is not shared by their female partners.
So, is the Antilopine a kangaroo or a wallaroo? The jury seems hung. ‘Although the Antilopine Kangaroos are taxonomically closer to the walleroos,’ Dawson writes, ‘in outward appearance they resemble the Red Kangaroos more, being slender and long-limbed, as befits their mobile lifestyle. In the Northern Territory they are often known as “Red kangaroos”.’ Others remark upon their gregarious nature, a propensity to gather together not only, kangaroo-like, with their conspecifics, but with other macropods, across what humans might term the species barrier, whereas wallaroos tend to be solitary creatures, or to gather only in small pods.
On the other hand, their nose is as bald as can be.
Half a million of them, it’s estimated there might be. If we imagine the Antilopine to be amongst the kangaroos not currently being seen in the Kimberley, we might have to reduce that number.